A particle (charge = 5.0 μC) is released from rest at a point x = 10 cm on the x-axis. If a 5.0-μC charge is held fixed at the origin, what is the kinetic energy of the particle after it has moved 90 cm?

Explanation:

Given

Two charges with charge

When the first charge is at on the x-axis and another at x=0 (origin)

there is only Potential Energy

Total Energy(E)=Kinetic Energy(K)+Potential Energy(U)

When First charge is at

There will be both Kinetic energy and potential Energy

As total Energy is constant therefore Kinetic Energy is

resonant frequency